The purpose of the STARD initiative is to improve the quality of reporting of diagnostic studies. The items in the checklist and flowchart can help authors to describe essential elements of the design and conduct of the study, the execution of tests, and the results. We arranged the items under the usual headings of a medical research article, but this is not intended to dictate the order in which they have to appear within an article.
The guiding principle in the development of the STARD checklist was to select items that would help readers judge the potential for bias in the study and to appraise the applicability of the findings. Two other general considerations shaped the content and format of the checklist. Firstly, the STARD group believes that one general checklist for studies of diagnostic accuracy, rather than different checklists for each field, is likely to be more widely disseminated and perhaps accepted by authors, peer reviewers, and journal editors. Although the evaluation of imaging tests differs from that of tests in the laboratory, we felt that these differences were more in degree than in kind. The second consideration was the development of a checklist specifically aimed at studies of diagnostic accuracy. We did not include general issues in the reporting of research findings, such as the recommendations contained in the uniform requirements for manuscripts submitted to biomedical journals.14
Wherever possible, the STARD group based the decision to include an item on evidence linking the item to biased estimates (internal validity) or to variations in measures of diagnostic accuracy (external validity). The evidence varied from narrative articles that explained theoretical principles and papers that presented the results of statistical modelling to empirical evidence derived from diagnostic studies. For several items, the evidence was rather limited.
A separate background document explains the meaning and rationale of each item and briefly summarises the type and amount of evidence.15
This background document should enhance the use, understanding, and dissemination of the STARD checklist.
The STARD group put considerable effort into the development of a flow diagram for diagnostic studies. A flow diagram has the potential to communicate vital information about the design of a study and the flow of participants in a transparent manner.16
A comparable flow diagram has become an essential element in the CONSORT standards for reporting of randomised trials.12,16
The flow diagram could be even more essential in diagnostic studies, given the variety of designs employed in diagnostic research. Flow diagrams in the reports of studies of diagnostic accuracy indicate the process of sampling and selecting participants (external validity); the flow of participants in relation to the timing and outcomes of tests; the number of subjects who fail to receive the index test or the reference standard, or both (potential for verification bias17–19
); and the number of patients at each stage of the study, which provides the correct denominator for proportions (internal consistency).
The STARD group plans to measure the impact of the statement on the quality of published reports on diagnostic accuracy with a before and after evaluation.13
Updates of the STARD initiative's documents will be provided when new evidence on sources of bias or variability becomes available. We welcome any comments, whether on content or form, to improve the current version.